Various known melt blowing processes have been described in "Superfine Thermoplastic Fibers" by Wente, Industrial and Engineering Chemistry, Volume 48, Number 8, Pages 1342-1346, August 1956, "Manufacture Of Superfine Organic Fibers", Naval Research Laboratory Report, Number 111437, 1954, and U.S. Pat. No. 3,676,242 to Prentice. Apparatuses suitable for use in such processes are described in "An Improved Device For The Formation Of Superfine, Thermoplastic Fibers", by K. D. Lawrence et al, Naval Research Laboratory Report, Number 5265, Feb. 11, 1959, and in U.S. Pat. No. 3,981,650 to Page.
Nonwoven mats produced by these and other currently known melt blowing processes and the apparatuses used therefor employ an extruder to force a hot melt of thermoplastic material through a row of fine orifices and directly into converging high velocity streams of heated gas, usually air, arranged on alternate sides of the extrusion orifices. Fibers of the thermoplastic material are attenuated within the gas stream, the fibers solidifying at a point where the temperature is low enough.